Thanks for this, rbwalt.
Since there are no responses (and none are really required...but) I just wanted to add my .02. While this link could easily be interpreted as a plug for Roger's products I think if you actually read it you'll see that the meat and potatoes of it is just good info. Yeah, Roger does make a statement as to how Ram Labs does their testing and the tolerances that are adhered to but there is no blatant self-promotion.
Mr. Modjeski - should you happen to read this post - know that your input is always welcome in my circle whether it be a response, a correction, a link to information on your website or a pertinent thread in your own circle. This goes for Frank Van Alstine, Steve Sammet, Jim Hagerman, & Dan Wright. I think AudioCircle is pretty fortunate to have a core group of sponsors that produce well engineered vacuum tube equipment and have a combined knowledge base that likely exceeds 100 years worth of no non-sense experience.
I think the well educated tube user needs to be aware of the various aspects of using tube equipment in one's system. Know that I do understand that most of us do possess the level of skill and knowledge already and that this post may, to most, be academic. This doesn't mean you need to become an engineer but it seems logical that you should have some knowledge about the one part in your audio chain that effects its sonic characteristics and that you the user have some control over that.
Haven't most of us who have taken the time to educate ourselves come to the conclusion that the vendors claiming to "properly" match output tubes on a bench or service tester such as the Hickok 539C or even the new Amplitrex figured out that this is possible? Can one of these portable units really take that set of tubes to a real world set of working conditions found in actual circuit applications? No, they cannot. Oh, you can probably do a fair job of matching small signal tubes. However I am quite confident in most of the current premier manufacturers have built QA and test equipment that can do the job of assuring us we are getting what we pay for, for the most part. Anyone who's done their homework knows that Roger has designed and built his own computerized test and run in equipment and has proven conclusively that the manufacturers of today have a looser set of standards than the those of the golden era of tube manufacturing, and looser than his. That is just a function of economics. So he puts those tubes through another round of testing and matching to guarantee his customers a product that you ain't gonna get off of eBay. And he does it for a fairly competitive price.
Again this is just my take on the current production tubescape.
